It is of course important to minimize spillage of fluids around both land based and off-shore wells. The problem with regard to both types of wells is identical in that spilled well fluids can cause pollution. With off-shore wells, the fluids can pollute the water surrounding the well; with on-shore wells the soil around the well, and in some cases the ground water also, can be polluted. The problem is particularly present with oil and gas wells and other wells dealing with harmful and hazardous materials.
As a consequence of drilling and servicing wells, fluids containing hydrocarbons and other chemicals are released and spilled from the well casing. For example, during drilling, pulling drill pipe from the well bore can release drilling mud containing hydrocarbons and other chemicals. In the reworking of wells pulling production tubing from the wells can likewise spill liquids. While swabbing (cleaning out) wells, fluids can be forced to the surface in large volumes, resulting in spills.
Minimizing spills around oil wells and the advantages of doing so have long been recognized. As early as 1871 inventions were patented for gathering the oil from well tubes as they are being withdrawn from the wells. The structures were called by various names including, catchers, pans, basins, containers and the like, and all function to prevent spills. U.S. Pat. No. 113,638 to Dewey, issued Apr. 11, 1871 shows this technology is almost as old as oil wells. As the oil industry progressed, refinements were made in the devices for catching spilled fluids around a well. For example, U.S. Pat. No. 1,448,172 to Wellensiek, issued Mar. 13, 1923 shows a spill catcher mounted on the outside of the oil well casing. In the 1924 patent to Schuyler, U.S. Pat. No. 1,507,628, a spill catcher is shown clamped on the outside of the casing. The spill catcher is formed in multiple sections with flanges and seals between the sections for ease in installation on and removal from the outside of the casing.
In off-shore applications such as the United States Patents to Roberts (U.S. Pat. No. 1,811,761, issued Jun. 23, 1931 and U.S. Pat. No. 1,867,030, issued Jul. 12, 1932), and to Grace (U.S. Pat. No. 2,077,044, issued Apr. 13, 1937), spill pans and structures located below the drill floor are shown for catching spilled liquids. The Roberts' patent '761 describes utilizing a pump to remove the oil and drilling mud from the pan. Roberts' '030 discloses pipe 46 and pump 47 for collecting the spilled fluids. The structure in the Grace patent '044 has a compressible seal clamped around the casing (FIG. 7) and a drainpipe 38 connected to a suitable sump or pump to remove fluids from the catch basin.
The 1962 to St. John, U.S. Pat. No. 3,023,808 and the 1990 U.S. Pat. No. 4,949,784, to Evans, shows structures mounted on the outside of the well. U.S. Pat. No. 5,121,794, to Hibdon, et al., issued Jun. 16, 1992 describes a structure that has a flange integrally formed in the bottom thereof so that it can be bolted into the well structure between a pair of opposed interfacing flange surfaces. U.S. Pat. No. 5,121,796, to Wigington, issued Jan. 16, 1992 shows a catch device which is bolted to a plate which is in turn welded to the outside of a piece of casing bolted into the well.
Thus, the problem and many proposed solutions have existed.